SiC (silicon carbide) excels over Si (silicon) in dielectric breakdown resistance, heat conductivity, etc. SiC is thus noted as a semiconductor favorable for application, for example, in inverters of hybrid vehicles, etc. A MISFET (metal insulator semiconductor field effect transistor) that uses SiC is anticipated for use as a high-voltage device favorable for inverters of hybrid vehicles, etc.
As an example of a MISFET that uses SiC, Patent Document 1 discloses an SiC semiconductor device that includes an n type SiC substrate, an n type drift layer formed on the SiC substrate, a p type well region formed in the drift layer, an n type source region formed in the p type well region, a gate insulating film formed on a front surface of the drift layer, and a gate electrode formed on the gate insulating film.